ABSTRACT: B, V, R, and I CCD frames were obtained for the Southern Galaxies NGC 5757, and IC 1091. The frames were analysed to derive standard photometric and geometric parameters such as integrated magnitudes and colors, dimensions and inclination. Radial luminosity profiles along several directions were calculated and combined to give one mean

Based on a 5ks Chandra ACIS-I observation of M31 on Nov 11 2009, we report a dramatic brightening of CXOM31 J004321.1+411751, [aka r3-7 (Kong et al. 2002 ApJ 577, 738), source 437 (Pietsch, Freyberg, and Haberl 2005 A&A 434, 483), RX J0043.3+4117 (Supper et al. 2001 A&A 373, 63)]. The spectrum on Nov 11 can be well fit with a power law with photon

M31 has been monitored by the HRC and ACIS detectors aboard Chandra from 1999 to 2002. We report here a summary of properties of X-ray sources in M31 with a focus on an ongoing Chandra/HST program to monitor X-ray transients in M31. By comparing individual X-ray images, more than 100 sources were found to be variable (half the total number observed

We present a second paper of a complete characterization of stars whose low-depth transits were discovered by the OGLE-III campaign to select the most promising candidates for spectroscopic confirmation. This paper follows a similar analysis to one previously performed in Gallardo et al. (2005, A&A, 431, 707). We present new optical and near-IR

The GAW project aims to test the feasibility of a new generation of Imaging Atmospheric Cherenkov Telescopes that join high flux sensitivity with Large Field of View capability. It consists of an array of 3 imaging Cherenkov telescopes each equipped with a Fresnel refractive lens of about 3.6 m2 geometrical area and an array of multi-anode

Carrying out detailed analyses on massive blue stars further than the Milky Way is a demanding task, however it is feasible and the best way to comprehend the stellar evolution in environments with different metallicity. We present the first quantitative study performed on a massive blue star sample belonging to NGC~55, about 1.9 Mpc away. The